Optimization of the copying of change recorded data by using spare flash capacity

ABSTRACT

A command is received to copy a first extent in a source volume to a second extent in a target volume, wherein the source volume and the target volume are in a copy relationship. In response to determining that it takes longer to copy all changed data of the first extent to the second extent than to copy all of the changed data of the first extent to a third extent and to copy all other data from the second extent to the third extent, operations are performed to copy all of the changed data of from the first extent to the third extent and to copy all of the other data from the second extent to the third extent. Operations are also performed to assign the third extent to replace the second extent in the target volume.

BACKGROUND

1. Field

Embodiments relate to optimization of the copying of change recordeddata by using spare flash capacity.

2. Background

A storage controller may be coupled to one or more of a plurality ofhosts. The storage controller may manage a plurality of storage devices,such as disk drives, tape drives, flash drives, etc., that are coupledto the storage controller. The plurality of hosts may access data storedin the storage devices via the storage controller.

Host applications that execute in the plurality of hosts may createlogical storage volumes, and subsequent to the creation of the logicalstorage volumes write to logical addresses of the logical volumes. Thehost applications may also read from logical addresses of the logicalstorage volumes.

The storage controller assigns physical storage to store data that isstored in the logical storage volumes. For example, the storagecontroller may assign one or more physical extents to each logicalstorage volume, where the physical extents may reside in storage devices(such as nearline storage, disk drives, tape drives, flash drives, etc.)coupled to the storage controller. Latency is the time interval betweeninitiating a query, transmission, or process, and receiving or detectingthe results, often given as an average value over a large number ofevents. The storage devices attached to or controlled by a storagecontroller may have different latencies. In general, a flash storage mayhave a lower latency than a disk storage or a nearline storage.

A point-in-time copy is a fully usable copy of a defined collection ofdata that contains an image of the data as it appeared at a single pointin time. The copy is considered to have logically occurred at that pointin time, but certain mechanisms may perform part or all of the copy atother times. A source volume and a target volume may be referred to bein a point-in-time copy relationship, if the target volume is apoint-in-time copy of the source volume.

SUMMARY OF THE PREFERRED EMBODIMENTS

Provided are a method, a system, and a computer program in which acommand is received to copy a first extent in a source volume to asecond extent in a target volume, wherein the source volume and thetarget volume are in a copy relationship. In response to determiningthat it takes longer to copy all changed data of the first extent to thesecond extent than to copy all of the changed data of the first extentto a third extent and to copy all other data from the second extent tothe third extent, operations are performed to copy all of the changeddata of from the first extent to the third extent and to copy all of theother data from the second extent to the third extent. Operations arealso performed to assign the third extent to replace the second extentin the target volume.

In additional embodiments, in response to determining that it takeslonger to copy all of the changed data of the first extent to the thirdextent and to copy all of the other data from the second extent to thethird extent than to copy all of the changed data of the first extent tothe second extent, the changed data from the first extent is copied tothe second extent.

In further embodiments, wherein a determination is made as to whether atier of storage in which the third extent resides has enough space toallocate the third extent with adequate space to allow copying of all ofthe changed data of from the first extent to the third extent and thecopying of all of the other data from the second extent to the thirdextent, prior to performing the copying of all of the changed data fromthe first extent to the third extent and the copying of all of the otherdata from the second extent to the third extent.

In still further embodiments, the first extent is maintained in a firsttype of storage, the second extent is maintained in a second type ofstorage, and the third extent is maintained in a third type of storage,wherein the third type of storage has a faster response time for readsand writes in comparison to the first type of storage or the second typeof storage.

In additional embodiments, the second type of storage is nearlinestorage or some other type of storage, and the third type of storage isflash storage or another type of storage that has a lower latency thanthe second type of storage.

In further embodiments, the source volume has a plurality of extents,wherein the extents of the source volume are copied to at least twodifferent types of storage that have different response times for readsand writes.

In certain embodiments, based on the percentage of changed data in thefirst extent, the first extent is copied to the second extent or thethird extent, wherein the copy relationship is a point-in-time copyrelationship.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers representcorresponding parts throughout:

FIG. 1 illustrates a block diagram of a computing environment comprisinga storage controller coupled to a host, in accordance with certainembodiments;

FIG. 2 illustrates a block diagram that shows the different types ofdata in extents, in accordance with certain embodiments;

FIG. 3 illustrates a block diagram that shows a standard copy mechanism,in accordance with certain embodiments;

FIG. 4 illustrates a block diagram that shows a flash-optimized copymechanism, in accordance with certain embodiments;

FIG. 5 illustrates a first flowchart that shows the optimization of acopy mechanism by using spare flash cache, in accordance with certainembodiments;

FIG. 6 illustrates a block diagram that shows a flash-optimized copymechanism for one extent and a standard copy mechanism for anotherextent, in accordance with certain embodiments;

FIG. 7 illustrates a second flowchart that shows the optimization of acopy mechanism by using spare flash cache, in accordance with certainembodiments;

FIG. 8 provides a graphical illustration that shows that at some pointthere is a breakeven point to copying data to better speed tier and thecost of copying data;

FIG. 9 illustrates a block diagram of a cloud computing environment, inaccordance with certain embodiments;

FIG. 10 illustrates a block diagram of further details of the cloudcomputing environment of FIG. 9, in accordance with certain embodiments;and

FIG. 11 illustrates a block diagram of a computational system that showscertain elements that may be included in the storage controller or thehost shown in FIG. 1, in accordance with certain embodiments.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings which form a part hereof and which illustrate severalembodiments. It is understood that other embodiments may be utilized andstructural and operational changes may be made,

There exists a need to ensure the fast copying of change-recorded datafrom one storage volume to another. There are many situations wherespare flash capacity may exist on a storage system. Certain embodimentsprovide a mechanism for optimizing the utilization of the spare flashcapacity on the storage system by determining a time required to copychange recorded data from one storage volume to other. Morespecifically, certain embodiments determine whether to copy changerecorded data from one extent to another based on the calculation oftime taken to copy the change recorded data by using a flash extent andwithout using a flash extent.

Exemplary Embodiments

FIG. 1 illustrates a block diagram of a computing environment 100comprising a storage controller 102 coupled to a host 104 via a networkor a direct link, in accordance with certain embodiments.

The storage controller 102 and the host 104 may comprise any suitablecomputational device including those presently known in the art, suchas, a personal computer, a workstation, a server, a mainframe, a handheld computer, a palm top computer, a telephony device, a networkappliance, a blade computer, a processing device, etc. The storagecontroller 102 and the host 104 may be elements in any suitable network,such as, a storage area network, a wide area network, the Internet, anintranet. In certain embodiments, storage controller 102 and the host104 may be elements in a cloud computing environment.

In certain embodiments, the storage controller 102 is coupled to thehost 104 via a suitable network such as the Internet, an intranet, astorage area network, etc. A host application 106 executes in the host104 and a storage management application 108 executes in the storagecontroller 102, where the host application 106 and the storagemanagement application 108 may be implemented in software, hardware,firmware or any combination thereof. The storage management application108 may include a process for copy optimization, where the process forcopy optimization manages how source extents 110 are copied to one ormore extents 112, 114 where extent 112 is a non-flash extent and extent114 is a flash extent. The non-flash extent 112 and/or the flash extent114 may be target extents 118 of the source extents 110, where a sourceand a target extent may be in a point-in-time copy relationship.

The storage controller 102 controls access to one or more storagedevices 118 a . . . 118 n that are coupled to the storage controller102. The storage devices 1148 . . . 118 n may include any suitablestorage devices such as magnetic disk drives, tape drives, solid statedrives (i.e., flash drives), nearline storage, etc.

The non-flash extent 112 takes a longer time to respond to input/output(I/O) operations in comparison to the flash extent 114. For example, theflash extent 114 may be stored in a solid state drive and the non-flashextent 112 may be stored in nearline storage. In certain embodiments,the storage management application 108 makes a determination as towhether to use the non-flash extent 112 or the flash extent 114 as thetarget extent of a source extent 110 when change-recorded data has to bepropagated to the target extent, where the determination may be based oncalculating whether using the flash extent 114 or the non-flash extent112 as the target extent improves system performance. It should be notedthat there may be significantly more non-flash extents 112 in comparisonto flash extents 114, as flash extents 114 may be relatively moreexpensive than non-flash extents 112 that are maintained in nearlinestorage or disk storage. If a non-flash extent is already in a copyrelationship with a source extent and only a very small amount of datachanges in the source extent, then it may be better to continue to usethe non-flash extent as the target extent by copying the small amount ofchanges over to the non-flash extent than to copy both changed andunchanged data to a flash extent and make the flash extent the targetextent.

FIG. 2 illustrates a block diagram 200 that shows the different types ofdata in extents, in accordance with certain embodiments. Unchanged data202 is shown via light shading 204. Change-recorded data (i.e., datathat has changed in the source extent since a point-in-time copy of asource extent to a target extent) 206 is shown in black, and unneededdata or free space is shown in white 112.

FIG. 3 illustrates a block diagram 300 that shows a “standard copy”mechanism, in accordance with certain embodiments. In FIG. 3, a sourceextent 302 and a target extent 304 are in a point-in-time copyrelationship, i.e., the data in the source extent 302 has been undergonea point-in-time copying to the target extent 304. Subsequently, areas306. 308. 310 of the source extent 302 may have new data written onthem. In a standard copy mechanism the new data 306, 308, 310 is copiedover to the target extent 304 as shown via the arrows 312, 314, 316.

FIG. 4 illustrates a block diagram 400 that shows a flash-optimized copymechanism, in accordance with certain embodiments.

In FIG. 4 the source extent 402 is in a point-in-time copy relationshipwith a target extent 404, where the source extent 402 and the targetextent 404 are stored in nearline storage. A flash extent 406 withadequate empty space is also available in the system to make the flashextent 406 into the target extent of the source extent 402.

In certain embodiments, when change-recorded data 408, 410, 412 isplaced in the source extent 402, then the storage management application108 may copy (413, 414, 416) the change-recorded data to the flashextent 406, and also copy the other data (the unchanged data 418, 420,422) top the flash extent 406 (the copying is shown via referencenumerals 424, 426, 428). Once the change-recorded data 408, 410, 412 andthe unchanged data 418, 420, 422 have been copied to the flash extent406, the flash extent 406 is assigned as the target extent of the sourceextent, and the target extent designation of the nearline extent 404 isremoved. This type of copying is referred to as a “flash-optimized” copymechanism.

FIG. 5 illustrates a first flowchart 500 that shows the optimization ofa copy mechanism by using spare flash cache, in accordance with certainembodiments. The operations shown in FIG. 5 may be performed by thestorage management application 108 that executes in the storagecontroller 102.

Control starts at block 502 in which the storage controller 102 receivesa request from the host application 106 to copy extent A to extent B,where both extent A and extent B may both be extents stored in nearlinestorage which has a slower response time than a flash extent that isstored in flash storage. Extent A (source extent) and extent B (targetextent) are in a copy relationship, and some data has changed (i.e.,change-recorded data) in extent A that is still not reflected in extentB.

Control proceeds to block 504 in which the storage controller 102calculates the “standard copy time” as the time required to copy allchanged data from extent A to extent B. Then the storage controller 102calculates (at block 506) the “flash-optimized copy time” as the timerequired to copy all changed data from extent A to the flash extent inparallel with copying all other data from extent B to the flash extent.

Control then proceeds to block 508 in which the storage controller 102determines whether the “flash-optimized copy time” is greater than the“standard copy time”. If not (“No” branch 510), control proceeds inparallel to blocks 512 and 514, where in block 512 the changed data iscopied from extent A to the flash extent, and in block 514 all otherdata (i.e., unchanged data) is copied from extent B to the flash extent.

Once the operations shown in block 512 and 514 are both over, thestorage controller 102 designates (at block 516) the flash extent intothe target extent instead of extent B.

If at block 508 in the storage controller 102 determines that the“flash-optimized copy time” is greater than the “standard copy time”(“Yes” branch 518), control proceeds to block 520 in which the storagecontroller 102 copies the changed data from extent A to extent B.

Therefore, FIG. 5 illustrates embodiments in which if time is saved byusing the flash extent then the flash extent is used as the targetextent, and if no time is saved by using the flash extent then extent B(non-flash extent that is less responsive to I/O than the flash extent)continues to be used as the target extent.

FIG. 6 illustrates a block diagram 600 that shows a flash-optimized copymechanism for one extent and a standard copy mechanism for anotherextent, in accordance with certain embodiments.

FIG. 6 shows two volumes 602, 604 each of which have two extents. Thesetwo volumes are called “Source Volume” 602 and “Target Volume” 5604.Each extent has 100 tracks in it. All extents of all volumes exist onnearline storage which takes 20 ms. for read and/or write operations.There is a significant amount of free flash storage 605 which takes 2ms. for write operations.

There exists a point-in-time copy relationship going from source volume602 to target volume 604. There has been I/O to the source volume 602after the point-in-time copy was formed causing the first extent (extentA 606) of the source volume to be 95% different than the matching extent(Extent C 608) of the target volume 604, and the second extent (Extent B610) to be 5% different than the matching extent (extent D 612) of thetarget volume 604.

At this point, the user may initiate a fast reverse restore on thepoint-in-time copy relationship to restore data. The followingcalculations may be performed for each of the two extents:

Extent 1 (i.e., extent A 606): Standard copy time=(20 ms read fromSource Volume+20 ms write to Target Volume)*95 tracks=3800 ms; andFlash-optimized copy time=(20 ms read from Source Volume+2 ms write toTarget Volume)*100 tracks=2200 ms.

Extent 2 (extent B 610): Standard copy time=(20 ms read from SourceVolume+20 ms write to Target Volume)*5 tracks=200 ms; andFlash-optimized copy time=(20 ms read from Source Volume+2 ms write toTarget Volume)*100 tracks=2200 ms.

In the above case, extent 1 (i.e., extent A 606) uses theflash-optimized copy and extent 2 (i.e., extent 610) uses the standardcopy. The saving seen by introducing flash-optimized copy in this casemay be 40% faster, as the optimized mechanism takes 2400 ms. and thenon-optimized mechanism takes 4000 ms.

FIG. 7 illustrates a second flowchart 700 that shows the optimization ofa copy mechanism by using spare flash cache, in accordance with certainembodiments. The operations shown in FIG. 7 may be performed by thestorage management application 108 that executes in the storagecontroller 102.

Control starts at block 702 in which a command is received by thestorage controller 102 to copy a first extent 110 (e.g., a nearlineextent) in a source volume to a second extent 112 (e.g. a nearlineextent) in a target volume, where the source volume and the targetvolume are in a copy relationship. Control proceeds to block 704 inwhich the storage controller 102 determines whether it takes longer tocopy all changed data of the first extent to the second extent than tocopy all of the changed data of the first extent to a third extent 114(e.g., a flash extent) and to copy all other data from the second extentto the third extent.

In response to determining that it takes longer to copy all changed dataof the first extent to the second extent than to copy all of the changeddata of the first extent to a third extent and to copy all other datafrom the second extent to the third extent (“Yes” branch 706 from block704), operations are performed to copy all of the changed data of fromthe first extent to the third extent (block 708) and to copy all of theother data from the second extent to the third extent (block 710).Operations are also performed (block 712) to assign the third extent toreplace the second extent in the target volume.

In response to determining that it takes longer to copy all of thechanged data of the first extent to the third extent and to copy all ofthe other data from the second extent to the third extent than to copyall of the changed data of the first extent to the second extent (“No”branch 714 from block 704), the changed data from the first extent iscopied to the second extent (block 716).

FIG. 8 provides a graphical illustration 800 that shows that at somepoint there is a breakeven point to copying data to better speed tierand the cost of copying data. In FIG. 8 the horizontal axis 802 showsthe amount of changed data and the vertical axis 804 the time requiredfor copying the changed data. The line 806 shows the time required forcopying (via standard copy) the changed data when the third extent(residing in the better speed tier, e.g., flash memory) is not used forthe copying, and the line 808 shows the time required for copying (viaflash-optimized copy) the changed data when the third extent (stored inthe better speed tier) is used for the copying. It can be seen thatbeyond the breakeven point 810 (i.e., when a greater percentage of datahas changed) it may be better not to use the third extent for thecopying. In other words, beyond the breakeven point 810 (i.e., when agreater percentage of data has changed) the cost of flash-optimized copyexceeds the cost of standard copy and the flash-optimized copy is not tobe used.

Therefore FIGS. 1-8 illustrate certain embodiments in which depending onthe latencies of available extents that may serve as a target extent fora source extent, a suitable available extent may be assigned as a newtarget volume over an existing target extent.

In further embodiments, a determination is made as to whether a tier ofstorage in which the third extent (i.e., the flash extent 114) resideshas enough space to allocate the third extent with adequate space toallow copying of all of the changed data of from the first extent (e.g.,nearline based source extent 110) to the third extent (i.e., flashextent) and the copying of all of the other data (i.e., unchanged data)from the second extent (target nearline extent) to the third extent(flash extent), prior to performing the copying of all of the changeddata from the first extent to the third extent and the copying of all ofthe other data from the second extent to the third extent.

In still further embodiments, the first extent is maintained in a firsttype of storage, the second extent is maintained in a second type ofstorage, and the third extent is maintained in a third type of storage,wherein the third type of storage has a faster response time for readsand writes in comparison to the first type of storage or the second typeof storage. In additional embodiments, the first type of storage and thesecond type of storage are nearline storage, and the third type ofstorage is flash storage. In certain embodiments, the first type ofstorage may be any type of storage, the second type of storage isnearline storage, and the third type of storage is flash storage.

In further embodiments, the source volume has a plurality of extents,wherein the extents of the source volume are copied to at least twodifferent types of storage that have different response times for readsand writes. In certain embodiments, based on the percentage of changeddata in the first extent, the first extent is copied to the secondextent or the third extent, wherein the copy relationship is apoint-in-time copy relationship. The larger the percentage of data thatis change-recorded data the higher the likelihood that theflash-optimized copy will improve the copying performance.

In certain alternative embodiments, both the source and target extentsexist on the same storage system. In this case, if there are very fewsimilarities between the extents there is a case where updating thesource volume to just point at the target extent in place of theexisting source extent may be much faster. The target volume, needing anew extent may then also be pointed at the old source extent to maintainits capacity. This may be done if the restore process being optimizedmay leave the target volume's data in an unusable state.

Cloud Computing Environment

Cloud computing is a model for enabling convenient, on-demand networkaccess to a shared pool of configurable computing resources (e.g.,networks, servers, storage, applications, and services) that can berapidly provisioned and released with minimal management effort orservice provider interaction.

Referring now to FIG. 9, an illustrative cloud computing environment 50is depicted. As shown, cloud computing environment 50 comprises one ormore cloud computing nodes 10 with which local computing devices used bycloud consumers, such as, for example, personal digital assistant (PDA)or cellular telephone 54A, desktop computer 54B, laptop computer 54C,and/or automobile computer system 54N may communicate. Nodes 10 maycommunicate with one another. They may be grouped (not shown) physicallyor virtually, in one or more networks, such as Private, Community,Public, or Hybrid clouds as described hereinabove, or a combinationthereof. This allows cloud computing environment 50 to offerinfrastructure, platforms and/or software as services for which a cloudconsumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 54A-N shownin FIG. 8 are intended to be illustrative only and that computing nodes10 and cloud computing environment 50 can communicate with any type ofcomputerized device over any type of network and/or network addressableconnection (e.g., using a web browser).

Referring now to FIG. 10, a set of functional abstraction layersprovided by cloud computing environment 50 (FIG. 9) is shown. It shouldbe understood in advance that the components, layers, and functionsshown in FIG. 10 are intended to be illustrative only and embodiments ofthe invention are not limited thereto.

Hardware and software layer 60 includes hardware and softwarecomponents. Examples of hardware components include mainframes, in oneexample IBM zSeries* systems; RISC (Reduced Instruction Set Computer)architecture based servers, in one example IBM pSeries* systems; IBMxSeries* systems; IBM BladeCenter* systems; storage devices; networksand networking components. Examples of software components includenetwork application server software, in one example IBM WebSphere*application server software; and database software, in one example IBMDB2* database software. *IBM, zSeries, pSeries, xSeries, BladeCenter,WebSphere, and DB2 are trademarks of International Business MachinesCorporation registered in many jurisdictions worldwide.

Virtualization layer 62 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers;virtual storage; virtual networks, including virtual private networks;virtual applications and operating systems; and virtual clients.

In one example, management layer 64 may provide the functions describedbelow. Resource provisioning provides dynamic procurement of computingresources and other resources that are utilized to perform tasks withinthe cloud computing environment. Metering and Pricing provide costtracking as resources are utilized within the cloud computingenvironment, and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal provides access to the cloud computing environment forconsumers and system administrators. Service level management providescloud computing resource allocation and management such that requiredservice levels are met. Service Level Agreement (SLA) planning andfulfillment provide pre-arrangement for, and procurement of, cloudcomputing resources for which a future requirement is anticipated inaccordance with an SLA.

Workloads layer 66 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation; software development and lifecycle management; virtualclassroom education delivery; data analytics processing; transactionprocessing; and the copy optimization processing applications (e.g., thestorage controller application 108) as shown in FIGS. 1-9.

Additional Embodiment Details

The described operations may be implemented as a method, apparatus orcomputer program product using standard programming and/or engineeringtechniques to produce software, firmware, hardware, or any combinationthereof. Accordingly, aspects of the embodiments may take the form of anentirely hardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,aspects of the embodiments may take the form of a computer programproduct. The computer program product may include a computer readablestorage medium (or media) having computer readable program instructionsthereon for causing a processor to carry out aspects of the presentembodiments.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present embodiments may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present embodiments.

Aspects of the present embodiments are described herein with referenceto flowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instruction.

FIG. 11 illustrates a block diagram that shows certain elements that maybe included in the host 114 or storage controller 112 in accordance withcertain embodiments. The system 1100 may include a circuitry 1102 thatmay in certain embodiments include at least a processor 1104. The system1100 may also include a memory 1106 (e.g., a volatile memory device),and storage 1108. The storage 1108 may include a non-volatile memorydevice (e.g., EEPROM, ROM, PROM, RAM, DRAM, SRAM, flash, firmware,programmable logic, etc.), magnetic disk drive, optical disk drive, tapedrive, etc. The storage 1108 may comprise an internal storage device, anattached storage device and/or a network accessible storage device. Thesystem 1100 may include a program logic 1110 including code 1112 thatmay be loaded into the memory 1106 and executed by the processor 1104 orcircuitry 1102. In certain embodiments, the program logic 1110 includingcode 1112 may be stored in the storage 1108. In certain otherembodiments, the program logic 1110 may be implemented in the circuitry1102. Therefore, while FIG. 11 shows the program logic 1110 separatelyfrom the other elements, the program logic 1110 may be implemented inthe memory 1106 and/or the circuitry 1102.

Certain embodiments may be directed to a method for deploying computinginstruction by a person or automated processing integratingcomputer-readable code into a computing system, wherein the code incombination with the computing system is enabled to perform theoperations of the described embodiments.

The terms “an embodiment”, “embodiment”, “embodiments”, “theembodiment”, “the embodiments”, “one or more embodiments”, “someembodiments”, and “one embodiment” mean “one or more (but not all)embodiments of the present invention(s)” unless expressly specifiedotherwise.

The terms “including”, “comprising”, “having” and variations thereofmean “including but not limited to”, unless expressly specifiedotherwise.

The enumerated listing of items does not imply that any or all of theitems are mutually exclusive, unless expressly specified otherwise.

The terms “a”, “an” and “the” mean “one or more”, unless expresslyspecified otherwise.

Devices that are in communication with each other need not be incontinuous communication with each other, unless expressly specifiedotherwise. In addition, devices that are in communication with eachother may communicate directly or indirectly through one or moreintermediaries.

A description of an embodiment with several components in communicationwith each other does not imply that all such components are required. Onthe contrary a variety of optional components are described toillustrate the wide variety of possible embodiments of the presentinvention.

Further, although process steps, method steps, algorithms or the likemay be described in a sequential order, such processes, methods andalgorithms may be configured to work in alternate orders. In otherwords, any sequence or order of steps that may be described does notnecessarily indicate a requirement that the steps be performed in thatorder. The steps of processes described herein may be performed in anyorder practical. Further, some steps may be performed simultaneously.

When a single device or article is described herein, it will be readilyapparent that more than one device/article (whether or not theycooperate) may be used in place of a single device/article. Similarly,where more than one device or article is described herein (whether ornot they cooperate), it will be readily apparent that a singledevice/article may be used in place of the more than one device orarticle or a different number of devices/articles may be used instead ofthe shown number of devices or programs. The functionality and/or thefeatures of a device may be alternatively embodied by one or more otherdevices which are not explicitly described as having suchfunctionality/features. Thus, other embodiments of the present inventionneed not include the device itself.

At least certain operations that may have been illustrated in thefigures show certain events occurring in a certain order. In alternativeembodiments, certain operations may be performed in a different order,modified or removed. Moreover, steps may be added to the above describedlogic and still conform to the described embodiments. Further,operations described herein may occur sequentially or certain operationsmay be processed in parallel. Yet further, operations may be performedby a single processing unit or by distributed processing units.

The foregoing description of various embodiments of the invention hasbeen presented for the purposes of illustration and description. It isnot intended to be exhaustive or to limit the invention to the preciseform disclosed. Many modifications and variations are possible in lightof the above teaching. It is intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto. The above specification, examples and data provide acomplete description of the manufacture and use of the composition ofthe invention. Since many embodiments of the invention can be madewithout departing from the spirit and scope of the invention, theinvention resides in the claims hereinafter appended. affiliates.

What is claimed is:
 1. A method, comprising: receiving, a command tocopy a first extent in a source volume to a second extent in a targetvolume, wherein the source volume and the target volume are in a copyrelationship; and in response to determining that it takes longer tocopy all changed data of the first extent to the second extent than tocopy all of the changed data of the first extent to a third extent andto copy all other data from the second extent to the third extent,performing: copying all of the changed data of from the first extent tothe third extent; copying all of the other data from the second extentto the third extent; and assigning the third extent to replace thesecond extent in the target volume.
 2. The method of claim 1, the methodfurther comprising: in response to determining that it takes longer tocopy all of the changed data of the first extent to the third extent andto copy all of the other data from the second extent to the third extentthan to copy all of the changed data of the first extent to the secondextent, copying the changed data from the first extent to the secondextent.
 3. The method of claim 1, wherein a determination is made as towhether a tier of storage in which the third extent resides has enoughspace to allocate the third extent with adequate space to allow copyingof all of the changed data of from the first extent to the third extentand the copying of all of the other data from the second extent to thethird extent, prior to performing the copying of all of the changed datafrom the first extent to the third extent and the copying of all of theother data from the second extent to the third extent.
 4. The method ofclaim 1, wherein the first extent is maintained in a first type ofstorage, the second extent is maintained in a second type of storage,and the third extent is maintained in a third type of storage, andwherein the third type of storage has a faster response time for readsand writes in comparison to the first type of storage or the second typeof storage.
 5. The method of claim 4, wherein the second type of storageis nearline storage or some other type of storage, and the third type ofstorage is flash storage or another type of storage that has a lowerlatency than the second type of storage.
 6. The method of claim 1,wherein the source volume has a plurality of extents, and wherein theextents of the source volume are copied to at least two different typesof storage that have different response times for reads and writes. 7.The method of claim 1, wherein based on the percentage of changed datain the first extent, the first extent is copied to the second extent orthe third extent, and wherein the copy relationship is a point-in-timecopy relationship.
 8. A system, comprising: a memory; and a processorcoupled to the memory, wherein the processor performs operations, theoperations comprising: receiving, a command to copy a first extent in asource volume to a second extent in a target volume, wherein the sourcevolume and the target volume are in a copy relationship; and in responseto determining that it takes longer to copy all changed data of thefirst extent to the second extent than to copy all of the changed dataof the first extent to a third extent and to copy all other data fromthe second extent to the third extent, performing: copying all of thechanged data of from the first extent to the third extent; copying allof the other data from the second extent to the third extent; andassigning the third extent to replace the second extent in the targetvolume.
 9. The system of claim 8, the operations further comprising: inresponse to determining that it takes longer to copy all of the changeddata of the first extent to the third extent and to copy all of theother data from the second extent to the third extent than to copy allof the changed data of the first extent to the second extent, copyingthe changed data from the first extent to the second extent.
 10. Thesystem of claim 8, wherein a determination is made as to whether a tierof storage in which the third extent resides has enough space toallocate the third extent with adequate space to allow copying of all ofthe changed data of from the first extent to the third extent and thecopying of all of the other data from the second extent to the thirdextent, prior to performing the copying of all of the changed data fromthe first extent to the third extent and the copying of all of the otherdata from the second extent to the third extent.
 11. The system of claim8, wherein the first extent is maintained in a first type of storage,the second extent is maintained in a second type of storage, and thethird extent is maintained in a third type of storage, and wherein thethird type of storage has a faster response time for reads and writes incomparison to the first type of storage or the second type of storage.12. The system of claim 11, wherein the second type of storage isnearline storage or some other type of storage, and the third type ofstorage is flash storage or another type of storage that has a lowerlatency than the second type of storage.
 13. The system of claim 8,wherein the source volume has a plurality of extents, and wherein theextents of the source volume are copied to at least two different typesof storage that have different response times for reads and writes. 14.The system of claim 8, wherein based on the percentage of changed datain the first extent, the first extent is copied to the second extent orthe third extent, and wherein the copy relationship is a point-in-timecopy relationship.
 15. A computer program product, the computer programproduct comprising: a computer readable storage medium having computerreadable program code embodied therewith, the computer readable programcode configured to perform operations on a processor, the operationscomprising: receiving, a command to copy a first extent in a sourcevolume to a second extent in a target volume, wherein the source volumeand the target volume are in a copy relationship; and in response todetermining that it takes longer to copy all changed data of the firstextent to the second extent than to copy all of the changed data of thefirst extent to a third extent and to copy all other data from thesecond extent to the third extent, performing: copying all of thechanged data of from the first extent to the third extent; copying allof the other data from the second extent to the third extent; andassigning the third extent to replace the second extent in the targetvolume.
 16. The computer program product of claim 15, the operationsfurther comprising: in response to determining that it takes longer tocopy all of the changed data of the first extent to the third extent andto copy all of the other data from the second extent to the third extentthan to copy all of the changed data of the first extent to the secondextent, copying the changed data from the first extent to the secondextent.
 17. The computer program product of claim 15, wherein adetermination is made as to whether a tier of storage in which the thirdextent resides has enough space to allocate the third extent withadequate space to allow copying of all of the changed data of from thefirst extent to the third extent and the copying of all of the otherdata from the second extent to the third extent, prior to performing thecopying of all of the changed data from the first extent to the thirdextent and the copying of all of the other data from the second extentto the third extent.
 18. The computer program product of claim 15,wherein the first extent is maintained in a first type of storage, thesecond extent is maintained in a second type of storage, and the thirdextent is maintained in a third type of storage, and wherein the thirdtype of storage has a faster response time for reads and writes incomparison to the first type of storage or the second type of storage.19. The computer program product of claim 18, wherein the second type ofstorage is nearline storage or some other type of storage, and the thirdtype of storage is flash storage or another type of storage that has alower latency than the second type of storage.
 20. The computer programproduct of claim 15, wherein the source volume has a plurality ofextents, wherein the extents of the source volume are copied to at leasttwo different types of storage that have different response times forreads and writes, and wherein based on the percentage of changed data inthe first extent, the first extent is copied to the second extent or thethird extent, and wherein the copy relationship is a point-in-time copyrelationship.